In REX/PSI Next Generation, the process parameters are defined centrally via the menu Simulation > Process parameters. These settings are crucial for the precise calculation and optimisation of the processes, as they have a direct influence on the quality and stability of the simulation. The following section describes the input options in the dialogue as well as the selection options for pressure input and other process-relevant parameters.

The dialogue for the process parameters is divided into two columns, each of which contains different categories of input values:

• Required parameters: These values must be specified by the user as they are essential for the calculation.
• Optional parameters: These values can be specified by the user, but are not mandatory. If these values are not entered, they are calculated automatically by the software. An example of this are parameters such as the dosing time or the location of the melt vortex formation (OSW).

This subdivision allows the user to control necessary process parameters manually, while less critical values can be determined automatically by the software, which increases user-friendliness.

A key function of the dialogue concerns the pressure input at the screw tip, which can be controlled in various ways depending on the process requirements. The user has three selection options:

• Manually enter back pressure: If Specified is activated, the user specifies a fixed back pressure that is used as a constant input for the simulation process. This option is suitable for standard processes where a fixed pressure is assumed at the screw tip.

• Mould characteristic curve (selection mould characteristic curve): This option activates the calculation of the pressure on the basis of a mould characteristic curve. The mould characteristic curve represents a mathematical description of the pressure curve as a function of throughput and speed, which enables precise simulation of the pressure build-up in specific moulds. This method is particularly suitable for complex moulds and variable process conditions.

• Tool (selection tool): Here, the calculation can be performed using a stored tool. This method uses specific mould data to determine the pressure curve in the simulation process. It is suitable for scenarios in which a specific mould model is used in the simulation.

Note: The selection of the options mould curve and mould is only available in REX. In each case, only one option can be selected for pressure input. As soon as a checkbox is activated, the input in the other fields is blocked to ensure that the pressure is only calculated using one of the defined methods.

In addition to the pressure input, the dialogue offers a choice between two calculation modes:

• Circumferential speed: The user can set the process to calculate based on the circumferential speed of the screw. This method makes it possible to control and optimise the material flow via the speed of the screw circumference.

• Throughput: Alternatively, the process can be calculated based on the throughput. In this case, the material flow is controlled directly via the specified quantity of material processed. Both calculation modes offer precise control over the simulation process, depending on the user's specific requirements.

In both cases, the process is calculated with the specified data and the software ensures that a functioning process is simulated.

Similar to the circumferential speed and throughput, the dialogue offers a selection option for calculating the cycle time:

• Cycle time based on speed: In this mode, the cycle time is calculated based on the screw speed specified by the user. This is a common method to control the process speed directly by the screw speed.

• Cycle time based on time: Alternatively, the user can specify that the cycle time is based on a preset time. The software then calculates the necessary parameters to ensure that the process runs within the specified cycle time.

These options provide flexibility in optimising the cycle and allow either time-based or speed-based control of the process.

After leaving the process parameter dialogue, a value range validation is performed automatically, in which the entered parameters are checked for plausibility and correctness. This check ensures that all the necessary data is correct before the simulation is started.

If the heating zone temperatures have not yet been defined in an earlier step, e.g. with the cylinder data, they must also be entered at this point. These temperatures are of great importance for material preparation and influence the melt quality as well as the entire process sequence.